Apparatus for and method of making finned tubing



H. W. BUNDY Feb. 7, 1933.

1,896,350 APPARATUS FOR AND METHOD OF MAKING FiNNED TUBING s Sheets-Sheet 1 Filed Dc. so, 1927 INVENTOR. A M

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' Feb. 7, 1933. H. WJBUNDY 1,896,350

APPARATUS FOR AND METHOD OF MAKING FINNED TUBING Filed Dec. 30, 1927 I 3 S he ets-Sheet 2 I l! A I rmnn n HI I fl' lL-lu .E l I I I I 15!] i 14 m Z'i K [a Z0 Z1 I I i can 'l 1 N VEN TOR,

A TTORNEY.

H. W. BUNDY Feb. 7, 1933 APPARATUS FOR AND METHOD OF MAKING FINNED TUBING Filed Deg. 30, 1927 3 Sheets-Sheet 3 TIIIIIII INVENTOR: v

71. flmdy ATTORNEY.

' die members. Fig. 8 is a perspective view of the comple- Patented Feb. 7, 1933 umrso STATES PATENT ol-"Fics HARBY W. BUNDY, 01" DETROIT, MICHIGAN, ASSIGNOR, BY MESNE ASSIGNMENTS, 1'0 BUNDY TUBING comrm,'or nmorr, MICHIGAN, A CORPORATION OF MICHIGAN manure ron. AND METHOD or mime rmrinn runnwe .Appllcation at December :0, 1921. Serial m5. 243,512.

' This invention relates to an a paratus for and method of making finned tu ing.

The invention is concerned particularly with the making of finned tubing wherein a helical fin for heat transferring -pu oses or the like is wound upon a preformed tu Accordin to the invention this preformed tube moves engthwise through the apparatus and at the same time is 'ven a rotational movement; A simplified%n winding apparatus is provided b this invention and also a method is afi'orde for efiecting these mentioned movements of the tube.

In the accompanying drawings: Fig. 1 is a side e ing apparatus, or winding head with some parts cut away and some parts in section,

showing a tube in place with the. stock' being wound thereon.

F1 1a is a view showing a tube wherein the is wound thereon in a modified manner. I

Fig. 2 is an end view of the'winding head looking from the left side ofFig. 1.

Figs. 3, 4, and 5 are sectional views taken w through the corresponding section lines of Fig. 2, showing the die construction for givin the fin stock an L shape in cross section be ore being wound on the tube.'

Fig. 6 is aplan view of 'the'winding head. Fig. 7 is a mental die member.

Fig. 9 is anenlarged view showing. in detail an operation on the fin just prior to its being wound upon the tube.

. Fig. 10 is a view partly in sectionof a further modified type of finned tube.

a further modified t made, wherein no pre ormed tube is used.

Referring to Fig. 1, a preformed tube of an desired construction is shown atl, and a sp ral finis shown as consistingof a helical fin 2'rising from a band of metal 3 flatly abutting the tube. Thus it will be seen that the fin stock is L shaped in cross section when it is placed upon thetube.

evation of the fin apply-' loose enough to permit this.

perspective view of. one of the Fig. 11 is a view similar to Fig. 10 showing. of tube which can be;

driven pressure rolls 5 and 6, the pressure roll 5 being mounted upon a shaft 7, and driven by means of pinions 8 and8a, there being an. interposed thrust bearing at 9. The pressure roll 6'is mounted upon a shaft 10 which car- .ries at its lower end a gear wheelll A drive shaft 12 carries the pinion 13 for meshing with the gear wheel 11 and also with the ear wheel 14: which drives the shaft upon w ich the inion 8 is mounted.

6 is mounted is journaled in a bearing block 15 which is adjustable so that the pressure roll 6 can be adjusted toward and away from and an ularl with respect to the pressure roll 5. or a justably mounting this bearing block a plurality of set screws 16 and 17, 18 and 1-9 may be provided which engage'the block on several sides to hold it in position. It will thus be seen that by manipulating these set screws the angular position of the pressuref'roll 6 and also the distance between this pressure rolland the roll 5 can be varied.

1 This adjustment affects also the gear 11., but pinion are the'intermeshing teeth with the The stock for the finned tube is preferably fed to therwinding head in flat strip form and it is run through suitable dies to give it an L shape in cross section just prior to being wound upon the tube. While this is preferable, the stock may be fed to themachine in angular form. However, referring to Fig.2, the strip stock is fed into the machine at the point carrying the appropriate legend. At this point the stock 1s engaged by the complementary die members 20 and 21. These die members are fitted together by means of pins 22 which extend through a r.- ture's 23 (Figs. 7 and 8). Preferably sprlngs 24 are interposed between the die members,

and in order to bring the die members together with operating .pressure a pivoted locking device 25 (Fig. 6) is provided. In a position shown in this figure the locking member holds the die together and ready for operation; In order to loosen the dies the locking member is shifted to dotted position and the coil springs force the dies apart.

T e shaft 10 upon which the pressure roll The headconsists primarily f This permits threading and originally setting 10o rotated. The stock having been fed or threaded into these rolls is engaged thereby with the fin portion 2 directly engaged between the pressure rolls. These rolls are brought together with sufficient pressure to pull the fin stock in through the dies so that no other stock feeding mechanism is required.

y The roll 6 is adjusted so that its fin engaging surface is at an-angle t0 the surfaces of the roll 5, as shown in Figs. 1 and 9. The pressure between these rolls is such as to compress the metal of the fin 2 with the metal near the outer edge of this fin 2 compressed more than it is next the inner edge or close to the tube. Inasmuch as the fin 2 is to be helically Wound the diameter at the outer edge of the tube' must necessarily be greater than the diameter of its inner edge or where. it abuts the tube, and by reason of the compressing of the metal and the thinning down of the fin near-its outer edge or rather the thinning down of the fin progressively from its inner to its outer edge this increase of diam- .ete'r is afforded. In fact the metal is so compressed that the fin is given a curvature by this compressing and preferably the curvature is such that the normal inside diameter of the fin is less than the outside diameter of the tube.

Thus as the machine is operated the fin stock moves in under the tube 1 where it is given a curvature by the compressing of the metal of the fin so that this finned stock moves upwardly and around the tube. The fin stock, by reason of having a normal inside diameter less than the outside diameter of the tube, grips the tube very tightly., 7

At this point description of how the tube is moved longitudinally and rotationally becomes necessary. It will be remembered that the finned stock is given a curvature so that it will grip the tube tightly. It is also forcibly fed by the action of the pressure rolls.-

Disposed immediately above the pressure rolls and above the tube is what may be termed a leaddie 26 (Figs. 1 and 6). This lead die has a slanting surface 27 and it is operation the tube is moved both rotationally and forwardly of the machine by reason of the winding of the finned stock thereon.

Also the pitch of the slanting surface-of the lead die determines the pitch of the helical'fin. As the lead die is interchangeable dies of a varied pitch can be used for effecting different pitched fins. As shown in Fig. 1 the tube engaging portion 3 of the stock is arranged so that adjacent convolutions abut each other and the lead die isdesigned to give the proper pitch to effect this construction. However, by referring to Fig.1a, the tube engaging portions are overlapped and to accomplish this all that is necessary is the use of a properly designed lea'd die to lessen the pitch of the helical fin. As shown in Fig. 10 the pitch of helical fin has been increased so that the several convolutions of fin stock are spaced apart from each other. This can'be accomplished by the use of a properly constructed lead die. Of course, it is within the invention to vary the width of the tube engaging band 3 of the stock so as to obtain overlapping without changing the lead die. The varying of the width of the tube engaging band'of the fin to obtain various other effects, with or without changing the lead die, is within the invention.' I

It is also possible with thelead here shown to manufacture a tube with overlapped sections but without any preformed tube on, the interior. Such as shown in Fig. 11.

After the fin has been applied to the tube, the whole tube may or may not be subjected to a bath of sealing material such as solder. Such a bath effects a tight -seal betweenthe tube and fin, but the tube is satisfactory for use without the application of solder.

' In making the form of tube shown in Fig. 11, the several convolutions are overlapped to form a tubular body: Instead-of employing a preformed tube around which the'convolutions are coiled,an arbor may be used for the overlapping coilsQ- The use of such' arbor, however, is old and generally understood by those in the art, and accordingly is not shown.

With a tube of thisnature it is preferable to complete and seal the convolutions by solder or other sealing metal to make the same fluid tight. I

I claim: Y

1. An apparatus .for forming finned tube which comprises, a pairof pressure rolls to which strip stock is guided for forming a fin with the stock engaged between the rolls',the engaging surfaces of the rolls being disposed at an angle to each other whereby to displace the metal and give the strip stock a curvature,

means for rotating the rolls so that'the rolls also feed the curved fin stock, and means for receiving a member in position to be encircled by the curved fin stock as it comes fromthe rolls, and means including a cam surface a ainst which the curved fin stock strikes for etl'ectingthe helical pitch of the fin.

2.An apparatus for forming finned tube comprising, a pair of pressure rolls to which the strip stock is guided for forming a fin with the stock engaged between the rolls, the engaging surfaces of the rolls being dlsposed at an angle to each other whereby to displace the metal'and; give the strip stock curvature,

means for rotating the rolls so that the rolls also feed the curved fin stock, and means for receiving a member in positoin to be encircled by the curved fin stock as .it comes from the rolls, and means including a cam surface against which the curved fin stock strikes for effecting the helical pitch of the fin, said means being removably held on the appara tus whereby means for effecting various pitches of the fin'stock can be utilized.

3; An apparatus for forming-finned tube comprising, a pair of pressure rolls arranged at right angles to each other having engaging surfaces between which is disposed. strip stock for forming a fin, one of these rolls being adjustable angularly with respect to the other, whereby the fin engaging surfaces can be angularly disposed to displace the metal of the fin and give the. fin a curvature, means for rotating the rolls, and means for positioning a member so that the curved fin,-

I is it is fed from the rolls, encircles'the mem- 4. In apparatus for forming finned tube comprising, means for receiving a cylindrical member, a pair of pressure rolls one of which rotates on an axis substantially parallel to the length of the said member, and the other ofwhich rotates'on an axis substantially at right angles to the length, means for guiding strip stock between the rolls, said rolls engaging the strip stock with sufficient pressure to displace the metal thereof and give the strip stock curvature, and means 'for rotating the rolls to feed the curved strip stock around the said cylindrical member.

5. An apparatus for forming finned tube comprising, means for receiving a cylindrical member, a pair of'pressure rolls one of which rotates on an axis substantially parallel to the length of the said member,and the other of which rotates on an axis substantially at right angles to the length of the tube, means for guiding strip stock between the'rolls, said rolls engaging the strip stock with sufficient pressure to displace the metal thereof and give the strip stock curvature, means for rotating the rolls to feed the curved strip stock around the said member,said rolls being adjustable angularly with respect to the other to vary the relative angle between their stock engaging surfaces, whereb the displacement of the metal and the resu ting curvature of the stock can be varied.

6. An apparatus for member, a pair of pressure rolls one'of which forming finned tube comprising, means for receivlng'a cylindrical rotates on an axis substantially parallel to the length of the said member, and the other of which rotates on an axis substantially at right f angles to the length of the tube, means for guiding strip stock between the rolls, said rolls engaging the strip stock with sufficient pressure to displace the metal thereof and give the strip stock curvature, means for rotating the rolls to feed the curved strip stock around the said member, the roll operating on an axis perpendicular tothe said member be igg adjustable angularly and toward: and

away from the cooperating roll whereby to vary the relative angularity of their stock engaging surfaces and accordingly vary the displacement of the metal and the resulting curvature of the fin. v

7. An apparatus for applying a helical fin to a preformed tube comprising, dies through which flat strip stock is fed, said dies giving the strip stock an E. shape in cross section, a pair of pressure rolls which engage the leg of the L which forms the fin, the engaging surface of these pressure rolls' being disposed at an angle to each other so as to compress this leg of the l, and give the stock the curvature, means for holding a tube, means for rotating the rolls to feed the stock, said tube being in a position whereby the fin wraps itself around the tube as it is fed from the rolls, and means engaging the fin substantially at the point where it wraps around the tube for giving the fin its helical pitch.

8. The method of winding a helical fin on a preformed tube which comprises, forcibly feeding thefinstock and winding the same stock around the tube with sufiicient tightness. to effect rotation of the tube.

9. The method of winding a helical fin on a core which comprises, feeding the fin stock. effecting a curvature of the finstock and then winding the fin stock on the core with sufficient tightness for the stock to grip the core and causerotation thereof upon the feeding of the stock.

'10. The method ofwinding a helical fin on-a preformed tube which comprises, effecting-a curvature in fiat strip fin stock, forcibly, -feeding this stock around the tube with the fin stock engaging the tube with sufficient pressure to effect rotation thereof due to the supporting the tube, eflecting a curvature .of

.flat fin stock so that normal inside diameter r is less than theexterior diameter of the tube,

iao

1 means, said fin stock holding the tube with.

suflicient tightness to carry the tube with it. f

forcibly feeding the fin stock around the tube with-the fin stock tightly gripping the. tube and effecting rotation thereof due to the forcible feeding of the fin stock.

12. The method of applying a helical on a preformed tube which comprises, loose- 1y supporting the tube, windin fin stock tightly on the tube, efli'ecting lengt wise movement" of the tube by causing rotation of the fin stock and advancing the fin stock by employing its helical formation and screw 13. The method of winding a helical fin on a preformed tube which comprises effecting a curvature on stripfin stock, forcibly feeding the stock around a tube, effecting rotation of'the tube by reason of forcibly feeding the stock, and effecting lengthwise movement of the tube by utilizing the screw efi'ect obtained from the .helical fin.

14. The method of winding a helical fin on i a preformed tube which comprises, effecting a curvature to strip fin stock, forcibly feeding this stock around the tube with the stock tightly engaging the tube, effecting rotation of the tube by reason of the forcible feeding of the fin stock, and simultaneously setting the pitch of the helical fin, as it is forcibly fed, and advancing the tube by reason of J the fin tightly engaging the same.

15. The method of winding a helical fin around a preformed tube which comprises, efiecting a curvature of flat strip stock for -for'ming a fin, forcibly feeding this stock around the tube with the stock tightly engaging the tube, employing die means for glvlng the finits helical'pitch, and effecting rotational and lengthwise movement of the tube by the forcible feeding of the stock.

16. In the process of making a helical Y winding for finned tubes or other purposes,

the steps of forming successive helical convolutions ;in -stock which comprises forcefully pushing stock, and simultaneously effecting a curvature in the-stock by the pushing instrumentality, by flowing the material of the stock, such'that successive convolutions of the pushed stock wind themselves into helical form upon an adjacent core.

17. An apparatus for forming a helical windingfrom strip metal stock, comprisin a pair of pressure rollers having oppose faces through which the strip stock passes, means for rotating at least one of the "polls to move the stock between them with'the opposed surface of the rollers being shaped to flow the metal of the strip stock to give the same a curvature, and means for positioning a core adjacent the rollers where the-strip stock emerges fromthe roll'sso that the strip -stock winds itself upon said core. In testimony whereof I a'flix my signature.

. HARRY iv -Bunny; 

